Slide-rule.



Patented Feb. 25, |902.

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f UNITE STATEs ATENIIl OFFICE.

JEAN HEINRICH CARL DENNERT, oF ALToNA, GERMANY, AssIGNoR To THE FIRM oF DENNERT a PAPE, oF ALToNA, PRUssIA, GERMANY.

4SLIDE-RULE.

SFECILFICATION forming part of Letters Patent No. 694,258, dated February 25, 1902.

Application filed July 25. 1901. Serial No. 69,728- (No model A To a/ZZ whom, it may concern:

Be it known that I, JEAN HEINRICH CARL DENNERT, a subject of the German Emperor, and a resident of Altona, in the Kingdom of Prussia, German Empire, have invented certain new and useful Improvements in Slide- Rules, of which the following is a specification.

The present invention relates to improvements in `slide-rules.

The object of the improvements is to provide means which allow and secure a proper fitting ofv the slide in the guide-grooves of the rule in spite of the shrinkage or expansion of the wood of which the rule is made, so that binding between the slide and the rule proper is reliably obviated and an easy and steady motion or operation of the slide always secured.

With this end in View my invention consists of certain novel features of construction and combinations of parts, as will behereinafter fully described and pointed out, with reference to the accompanying drawing, in Which- Figure lis a top or plan view of my im` Vout the several views.

The improved slide-rule consists of two wooden parallel bars or side pieces a a, preferably lined with Celluloid plates a and connected by a bottom plate c, capable of yield! ing in a transverse direction, and of a wooden slide b, likewise lined at top and bottom with celluloidplates b and arranged inwellknown manner, so as to slide with lateral tongues b2 in corresponding guide-grooves a2 of the parallel bars a. The bottom plate may be made, preferably, of celluloid and slightly curved outwardly in its middle portion, as shown in the drawing, so as to insure a yielding of such bottom' plate in a transverse direction to the rule., e'

The above-described.arrangement of the lbottom plate enables the slide to lit always readily and snugly between the parallel bars and to be moved along therein without any binding, even if the wood of the slide has somewhat expandedin the transverse direction', because the yielding bottom plate allows the parallel bars to correspondingly move a small distance apart. O11 the other hand, when the slide or its wood,respectively, shrinks the yielding bottom plate correspond-- ingly contracts the said vparallel bars, thereby securing the required proper contact between the latter and the slide. The disadvanta geously-acting alterations of the dimensions of the wood (shrinkage or expansion) caused vby the inilue'ncevof weather or changes inthe temperature, respectively, are thus reliably neutralized.

Finally, it may here 'be stated that slide rules are made or manufactured, as is well known, only of such woodwhich does not eX- pand or shrink in its longitudinal direction.y

Having fully described my invention, what I claim, and desire to secure by Letters Patent, is

1. Aslide-rulecomprisingparallel barsprovided with a guide-groove in their proximate faces, a slide slidable along and guided by said groove, and a more or less resilient supporting-plate, to which the parallel bars are secured, said plate provided with a longitudinal outwardly-curved center portion or bulge, for the purpose set forth.

2,. A slide-rule, comprising parallel bars, a slide slidable between and along said bars and a supporting-plaie to which said bars are secured, said plate extending throughout the length of the bars and adapted to expand and contract in a direction at right angles to the direction of motion of the slide, forthe purpose set forth.

JEAN HEINRICH CARL DENNERT. 

